From 212aef46ba4dc831eba9c16603b02ace4f8dd909 Mon Sep 17 00:00:00 2001 From: Xue jiufei Date: Thu, 22 May 2014 10:42:32 +1000 Subject: [PATCH] ocfs2: fix umount hang while shutting down truncate log Revert XXXX because it may cause umount hang while shutting down truncate log. fix NULL pointer dereference when dismount and ocfs2rec simultaneously The situation is as followes: ocfs2_dismout_volume -> ocfs2_recovery_exit -> free osb->recovery_map -> ocfs2_truncate_shutdown -> lock global bitmap inode -> ocfs2_wait_for_recovery -> check whether osb->recovery_map->rm_used is zero Because osb->recovery_map is already freed, rm_used can be any other values, so it may yield umount hang. To prevent NULL pointer dereference while getting sys_root_inode, we use a osb_tl_disable flag to disable schedule osb_truncate_log_wq after truncate log shutdown. Signed-off-by: joyce.xue Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton --- fs/ocfs2/alloc.c | 6 +++++- fs/ocfs2/ocfs2.h | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c index b4deb5f750d9..9d8fcf2f3b94 100644 --- a/fs/ocfs2/alloc.c +++ b/fs/ocfs2/alloc.c @@ -6046,7 +6046,8 @@ static void ocfs2_truncate_log_worker(struct work_struct *work) void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb, int cancel) { - if (osb->osb_tl_inode) { + if (osb->osb_tl_inode && + atomic_read(&osb->osb_tl_disable) == 0) { /* We want to push off log flushes while truncates are * still running. */ if (cancel) @@ -6223,6 +6224,8 @@ void ocfs2_truncate_log_shutdown(struct ocfs2_super *osb) int status; struct inode *tl_inode = osb->osb_tl_inode; + atomic_set(&osb->osb_tl_disable, 1); + if (tl_inode) { cancel_delayed_work(&osb->osb_truncate_log_wq); flush_workqueue(ocfs2_wq); @@ -6254,6 +6257,7 @@ int ocfs2_truncate_log_init(struct ocfs2_super *osb) * until we're sure all is well. */ INIT_DELAYED_WORK(&osb->osb_truncate_log_wq, ocfs2_truncate_log_worker); + atomic_set(&osb->osb_tl_disable, 0); osb->osb_tl_bh = tl_bh; osb->osb_tl_inode = tl_inode; diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h index 8d64a97a9d5e..bbec539230fd 100644 --- a/fs/ocfs2/ocfs2.h +++ b/fs/ocfs2/ocfs2.h @@ -422,6 +422,7 @@ struct ocfs2_super struct inode *osb_tl_inode; struct buffer_head *osb_tl_bh; struct delayed_work osb_truncate_log_wq; + atomic_t osb_tl_disable; /* * How many clusters in our truncate log. * It must be protected by osb_tl_inode->i_mutex. -- 2.39.5